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Jim Feldmann

Joined: 01 Sep 2008
Posts: 54
Location: Burbank, CA

Posted: Sat Mar 28, 2009 6:38 pm Post subject: Near disaster

I had an engine failure on takeoff today.  Fortunately it was a long runway and it happened at 10 feet altitude.  No injuries, no damage, and no idea why it happened.  



Actually, the engine (Rotax 912 ULS) did not stop.  It was running smoothly during taxi and warm up.  Mag check was fine.  I held short for 5 minutes or so for incoming traffic, running the engine from 2500 to 4000 for short periods.  No problems.  On takeoff, the engine pulled cleanly to 5000+ for the 5 or 6 seconds it took to break ground, then suddenly started running very rough and dropped to 2500 rpm or so.  I immediately pulled the throttle to idle and landed.  



While taxiing back to the hanger it ran fine, I tried full throttle again a couple of times and it ran perfectly.  So what I have is an intermittent or one time problem that could be deadly.



I don't think it was ignition related, because if it was a failure of one "mag" it would have run much better than it did, and if both failed, it wouldn't have run at all.  That leaves fuel or mechanical.  



The carbs have recently been rebuilt.  After I calmed down, I checked the float bowls, they are clean, the gascolator is clean and the fuel pump is putting out 4.5 psi., right on spec.  Fuel is flowing freely through all of the inline filters and the header tank is full.  I did recently drain all of the fuel out of the airplane to fix a leak in the header tank.  Then I simply refilled the tanks from the top.  Could there have been air in the fuel line between the header tank and the gascolater?  The engine had been run for half an hour or so since then, but mostly at low throttle.



I have checked the throttle linkages also.  No problem there.  The plugs look good too, but my runups on taxi back would have obscured the evidence anyway.



My A&E suggested that it could be sticky valve.



Has anyone experienced a similar problem?  Any thoughts on what to look for?  I'm very hesitant to fly it again until I know what caused the problem

_________________
Jim Feldmann
Kitfox IV Speedster / 912 lost to prop failure
Building a Kitfox 5 Voyager

Tom Jones

Joined: 12 Mar 2006
Posts: 752
Location: Ellensburg, WA

Posted: Sat Mar 28, 2009 6:52 pm Post subject: Re: Near disaster

 	  Quote: 	
		  Actually, the engine (Rotax 912 ULS) did not stop. It was running smoothly during taxi and warm up. Mag check was fine. I held short for 5 minutes or so for incoming traffic, running the engine from 2500 to 4000 for short periods. No problems. On takeoff, the engine pulled cleanly to 5000+ for the 5 or 6 seconds it took to break ground, then suddenly started running very rough and dropped to 2500 rpm or so. I immediately pulled the throttle to idle and landed. 	




This sounds like a fuel flow problem.  Alao, a problem soon after maintenance often has some relation to the maintenance.  Were fuel lines to the header tank removed and/or replaced?



How about the rest of the fuel lines?



Any chance the fuel had a slug of water in it?

_________________
Tom Jones
Classic IV
503 Rotax, 72 inch Two blade Warp
Ellensburg, WA

propellerdesign(at)tele2.
Guest

Posted: Sat Mar 28, 2009 11:07 pm Post subject: Near disaster

I agree with Tom ? possibility of Carb Ice.



Jan

---

leach(at)infogen.net.nz
Guest

Posted: Sun Mar 29, 2009 1:08 am Post subject: Near disaster

Jim, This sounds like a classic case of carb ice to me.   On cold humid

mornings my 912 has almost stopped several times while taxiing.  I pull the

carb heat on and the engine immediately runs perfectly.  I then give the

engine a really good warm up and apply carb heat for 30 seconds or so before

applying full power for takeoff, and have never had a problem.   If your

engine quit on a cold humid day and you don't have carb heat I would bet you

had carb ice.



Brian Leach

New Zealand

Avid 912 taildragger.

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Sun Mar 29, 2009 2:50 am Post subject: Near disaster

Maybe vapor lock. You ran the engine for 5 minutes on ground at up to  

nearly full throttle, so something might have gotten hotter than it  

would in flight, and heated up a fuel line that wouldn't normally  

have gotten that hot before. Look for high points in the fuel system,  

or places that exhaust heat might be too close to the fuel lines.  

Good save, Jim.



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 622.1 hrs

Sensenich 62x46

Electroair direct-fire ignition system

Status: flying





On Mar 28, 2009, at 10:39 PM, Jim Feldmann wrote:



 	  Quote: 	
		   

 <feldesign(at)earthlink.net>



 I had an engine failure on takeoff today.  Fortunately it was a  

 long runway and it happened at 10 feet altitude.  No injuries, no  

 damage, and no idea why it happened.



 Actually, the engine (Rotax 912 ULS) did not stop.  It was running  

 smoothly during taxi and warm up.  Mag check was fine.  I held  

 short for 5 minutes or so for incoming traffic, running the engine  

 from 2500 to 4000 for short periods.  No problems.  On takeoff, the  

 engine pulled cleanly to 5000+ for the 5 or 6 seconds it took to  

 break ground, then suddenly started running very rough and dropped  

 to 2500 rpm or so.  I immediately pulled the throttle to idle and  

 landed.



 While taxiing back to the hanger it ran fine, I tried full throttle  

 again a couple of times and it ran perfectly.  So what I have is an  

 intermittent or one time problem that could be deadly.



 I don't think it was ignition related, because if it was a failure  

 of one "mag" it would have run much better than it did, and if both  

 failed, it wouldn't have run at all.  That leaves fuel or mechanical.



 The carbs have recently been rebuilt.  After I calmed down, I  

 checked the float bowls, they are clean, the gascolator is clean  

 and the fuel pump is putting out 4.5 psi., right on spec.  Fuel is  

 flowing freely through all of the inline filters and the header  

 tank is full.  I did recently drain all of the fuel out of the  

 airplane to fix a leak in the header tank.  Then I simply refilled  

 the tanks from the top.  Could there have been air in the fuel line  

 between the header tank and the gascolater?  The engine had been  

 run for half an hour or so since then, but mostly at low throttle.



 I have checked the throttle linkages also.  No problem there.  The  

 plugs look good too, but my runups on taxi back would have obscured  

 the evidence anyway.



 My A&E suggested that it could be sticky valve.



 Has anyone experienced a similar problem?  Any thoughts on what to  

 look for?  I'm very hesitant to fly it again until I know what  

 caused the problem



 --------

 Jim Feldmann, 3rd owner

 1994 Kitfox IV Speedster / 912

 Working on my Sport Pilot Certificate





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 36597#236597

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

marwynne(at)verizon.net
Guest

Posted: Sun Mar 29, 2009 4:52 am Post subject: Near disaster

Look at the carburetor boots.  I had one with a crack in it cause the same 

type of problem..



Marwynne



---

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sun Mar 29, 2009 5:26 am Post subject: Re: Near disaster

Carb ice wouldn't make it suddenly lose 50% of its rpm. Now maybe a vapor lock issue might have. Just something to consider in your diagnostics.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

PMorel

Joined: 09 Jul 2007
Posts: 62
Location: Locust Grove, GA USA

Posted: Sun Mar 29, 2009 5:34 am Post subject: Near disaster

I wouldn't rule out vacuum lines.

   From: Jim Feldmann <feldesign(at)earthlink.net>

To: kitfox-list(at)matronics.com

Sent: Saturday, March 28, 2009 10:39:02 PM

Subject: Near disaster

--> Kitfox-List message posted by: "Jim Feldmann" <feldesign(at)earthlink.net (feldesign(at)earthlink.net)>

I had an engine failure on takeoff today.  Fortunately it was a long runway and it happened at 10 feet altitude.  No injuries, no damage, and no idea why it happened.  

Actually, the engine (Rotax 912 ULS) did not stop.  It was running smoothly during taxi and warm up.  Mag check was fine.  I held short for 5 minutes or so for incoming traffic, running the engine from 2500 to 4000  for short periods.  No problems.  On takeoff, the engine pulled cleanly to 5000+ for the 5 or 6 seconds it took to break ground, then suddenly started running very rough and dropped to 2500 rpm or so.  I immediately pulled the throttle to idle and landed.  

While taxiing back to the hanger it ran fine, I tried full throttle again a couple of times and it ran perfectly.  So what I have is an intermittent or one time problem that could be deadly.

I don't think it was ignition related, because if it was a failure of one "mag" it would have run much better than it did, and if both failed, it wouldn't have run at all.  That leaves fuel or mechanical.  

The carbs have recently been rebuilt.  After I calmed down, I checked the float bowls, they are clean, the gascolator is clean and the fuel pump is putting out 4.5 psi., right on spec.  Fuel is flowing freely through all of the inline filters  and the header tank is full.  I did recently drain all of the fuel out of the airplane to fix a leak in the header tank.  Then I simply refilled the tanks from the top.  Could there have been air in the fuel line between the header tank and the gascolater?  The engine had been run for half an hour or so since then, but mostly at low throttle.

I have checked the throttle linkages also.  No problem there.  The plugs look good too, but my runups on taxi back would have obscured the evidence anyway.

My A&E suggested that it could be sticky valve.

Has anyone experienced a similar problem?  Any thoughts on what to look for?  I'm very hesitant to fly it again until I know what caused the problem

--------

Jim Feldmann, 3rd owner

1994 Kitfox IV Speedster / 912

Working on my Sport Pilot Certificate

Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=236597#236597http://www.matronics.com/Navigator?Kitfox-List

 [quote][b]

_________________
Paul Morel
912 Speedster
Locust Grove, GA

www.WingsAirPhotos.com

mikelaundy(at)yahoo.co.uk
Guest

Posted: Sun Mar 29, 2009 6:51 am Post subject: Near disaster

Jim,



I had an engine cut during ground runs, I had previously drained all the fuel and refuelled the wing tanks with fresh fuel after the winter layup.



I discovered the header tank was empty as there was an airlock in the vent line. Blowing through the port tank filler cap pitot tube with the starboard tank fuel valve off, forced fuel into the header tank and cleared the airlock allowing  the header tank to fill. Since then no problems.  (In my aircraft the header tank vent goes to only the starboard tank).



My header tank vent line is also secured by nylock ties, if any of them are too tight it could restrict the header tank venting.



Mike Laundy

Kitfox III, Rotax 582

Cornwall

England



--- On Sun, 29/3/09, Jim Feldmann <feldesign(at)earthlink.net> wrote:

[quote]

From: Jim Feldmann <feldesign(at)earthlink.net>

Subject: Near disaster

To: kitfox-list(at)matronics.com

Date: Sunday, 29 March, 2009, 3:39 AM



--> Kitfox-List message posted by: "Jim Feldmann" <[url=/mc/compose?to=feldesign(at)earthlink.net]feldesign(at)earthlink.net[/url]>



I had an engine failure on takeoff today.  Fortunately it was a long runway and it happened at 10 feet altitude.  No injuries, no damage, and no idea why it happened.  



Actually, the engine (Rotax 912 ULS) did not stop.  It was running smoothly during taxi and warm up.  Mag check was fine.  I held short for 5 minutes or so for incoming traffic, running the engine from 2500 to 4000 for short periods.  No problems.  On takeoff, the engine pulled cleanly to 5000+ for the 5  or 6 seconds it took to break ground, then suddenly started running very rough and dropped to 2500 rpm or so.  I immediately pulled the throttle to idle and landed.  



While taxiing back to the hanger it ran fine, I tried full throttle again a couple of times and it ran perfectly.  So what I have is an intermittent or one time problem that could be deadly.



I don't think it was ignition related, because if it was a failure of one "mag" it would have run much better than it did, and if both failed, it wouldn't have run at all.  That leaves fuel or mechanical.  



The carbs have recently been rebuilt.  After I calmed down, I checked the float bowls, they are clean, the gascolator is clean and the fuel pump is putting out 4.5 psi., right on spec.  Fuel is flowing freely through all of the inline filters and the header tank is full.  I did recently drain all of the fuel out of the airplane to fix a  leak in the header tank.  Then I simply refilled the tanks from the top.  Could there have been air in the fuel line between the header tank and the gascolater?  The engine had been run for half an hour or so since then, but mostly at low throttle.



I have checked the throttle linkages also.  No problem there.  The plugs look good too, but my runups on taxi back would have obscured the evidence anyway.



My A&E suggested that it could be sticky valve.



Has anyone experienced a similar problem?  Any thoughts on what to look for?  I'm very hesitant to fly it again until I know what caused the problem



--------

Jim Feldmann, 3rd owner

1994 Kitfox IV Speedster / 912

Working on my Sport Pilot Certificate





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=236597#236========================http://www.matronics.com/Nav=               - MATRONICS cs.com" bsp;               -Matt Dralle, List Adontribution" target="_blank">http://www.matronics.com/contribution

           [quote][b]

darinh

Joined: 20 Apr 2006
Posts: 327
Location: Utah

Posted: Sun Mar 29, 2009 8:34 am Post subject: Re: Near disaster

Jim,



I had a very similar thing happen to me in my Kitfox (914).  I figured it was something with the turbo as it would run fine up to about 4000 rpm.  After re-adjusting the waste gate several times and tinkering with virtually everything else, I found that my final fuel filter was 95% coated with a pasty coating of something.  At lower throttle, my pumps could force just enough fuel through to keep the engine running as it should but when I hit take-off power the fuel flow was not enough and the engine would cough and sputter.  What that "something" was is still a bit of a mystery and some will argue with me but I am 100% sure I had an incompatibility between my fuel and mil6000 fuel hose.  I have 3 filters in my system, two of which are connected to the tanks via aluminum tubing...my last filter was the only one with the mil6000 hose and was the only one that was plugged.  I have replaced the filter and lines and the new filter is clean as the day it went in.  



You said your gascolator is clean...do you have any other filters in the system that may be plugged?

_________________
Darin Hawkes
Series 7
914 Turbo
Kaysville, Utah

Jim Feldmann

Joined: 01 Sep 2008
Posts: 54
Location: Burbank, CA

Posted: Sun Mar 29, 2009 8:46 am Post subject: Re: Near disaster

Thank you all for your replies and suggestions.  I will check into all of them.  



Tom; yes, I removed the header tank, corrected a slow leak in the bottom fitting and then reinstalled the tank using the original fuel and vent lines, which are about a year old and in good shape.



The possibility of water in the fuel or carb ice are remote.  It was 2:30 PM on a clear and dry, Sunny California day.  Ambient temp 78 degrees, humidity about 50%.  I don't know the dew point, but it would have been low.  I checked for water in the gascolater before the flight and found none.  (I have never found even a drop in either tank or in the gascolater.)

I will carefully check the entire fuel system for contamination.  If anyone has any new thoughts, please add them to the list.

_________________
Jim Feldmann
Kitfox IV Speedster / 912 lost to prop failure
Building a Kitfox 5 Voyager

Jim Feldmann

Joined: 01 Sep 2008
Posts: 54
Location: Burbank, CA

Posted: Sun Mar 29, 2009 9:09 am Post subject: Re: Near disaster

Darrin:  I have filters in the lines from the wing tanks to the header tank.  There is no filter on the header tank vent line, which goes to the right wing tank.  I'm thinking that the header tank could still vent, giving 15 minutes or more of gas at full throttle, even if both filters were plugged.  There is no filter between the header tank and the gascolater.



I will check the filters anyway.  Thanks.

_________________
Jim Feldmann
Kitfox IV Speedster / 912 lost to prop failure
Building a Kitfox 5 Voyager

thesupe(at)hotmail.com
Guest

Posted: Sun Mar 29, 2009 11:24 am Post subject: Near disaster

I had a problem with my Avid MK IV when it had the 582 in it.  The plane has an about 1 1/2 quart header tank.  I took off and when I got to about 450' it started to spit and sputter and would only hold about 4500 RPM.  I ended up landing in a neighbors hayfield with no damage.  I also had filters between the tanks and the header tank.  I was just using one tank at the time.  Turned out that the filter was plugging enough to restrict the flow to where I wasn't getting enough fuel at full throttel to keep up to the demand of the engine.  When the header tank started to run out C it started to miss and spit.  Steve Winder at Airdale/Avid said to never have a filter in a gravity flow area as it doen't take much to restrict the flow C it the filter is between the header tank and the fuel pump C the header tank may catch some of the junk in the lines that would otherwise get to the filter and also the fuel pump with help the flow rate.  Just another thought.  Take care C  Jim Chuk

 	  Quote: 	
		   Subject: Re: Near disaster

 From: feldesign(at)earthlink.net

 Date: Sun C 29 Mar 2009 10:09:30 -0700

 To: kitfox-list(at)matronics.com

 Darrin: I have filters in the lines from the wing tanks to the header tank. There is no filter on the header tank vent line C which goes to the right wing tank. I'm thinking that the header tank could still vent C even if both filters were plugged. There is no filter between the header tank and the gascolater.

 I will check the filters anyway. Thanks.

 --------

 Jim Feldmann C 3rd owner

 1994 Kitfox IV Speedster / 912

 Working on my Sport Pilot Certificate

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=236677#236677

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Tom Jones

Joined: 12 Mar 2006
Posts: 752
Location: Ellensburg, WA

Posted: Sun Mar 29, 2009 12:08 pm Post subject: Re: Near disaster

 	  Quote: 	
		  Tom; yes, I removed the header tank, corrected a slow leak in the bottom fitting and then reinstalled the tank using the original fuel and vent lines, which are about a year old and in good shape. 	




When the flexible material lines are pushed on to fittings the fitting can cut a little flapper on the inside of the line that works like a check valve when the flow increases.  Also make sure there are no kinks.  You probably have checked this already.

_________________
Tom Jones
Classic IV
503 Rotax, 72 inch Two blade Warp
Ellensburg, WA

Fox5flyer
Guest

Posted: Sun Mar 29, 2009 12:16 pm Post subject: Near disaster

Glad to hear that you had that hay field below you,  Jim.   I tend to agree with Steve.  By putting filters into the  wing tank feeder lines it not only adds additional choke points, but also more  places to leak and clog up.  The header tank is designed to sit in the low  point of the fuel system and makes a great gascolator.  I have my filter,  and the only filter I have (a high flow sintered bronze unit by Earls  Performance Products), on my firewall as the last line of defense.  I also  used 3/8 ID fuel line all the way to the engine.  It's my belief that,  within reason, the bigger fuel line equals better flow due to less restriction  which equals fewer problems.

 Deke Morisse

Mikado Michigan

S5/Subaru/CAP 402+  TT

"The aim of an argument or discussion should not be victory, but  progress."

- Joseph Joubert

  

 

 

 [quote]   ---

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sun Mar 29, 2009 1:47 pm Post subject: Near disaster

Strainers go before a pump, filters after and the gascolator at the lowest

point.  I know some disagree with that statement... That's ok.



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

dafox(at)ckt.net
Guest

Posted: Sun Mar 29, 2009 5:54 pm Post subject: Near disaster

I had the same problem three years ago.  Changed all the fuel lines, checked 

needles valves in carbs, checked fuel flow ( 10 gals an hour )  also 

installed inline fuel pump, everything checked Ok, still the same problem. i 

nstalled a new fuel pump, and that was the problem, the engine has been 

runing perfect ever sence, and that was three years ago.  You might think 

about installing a new fuel pump.

            David Yeamans

            Kitfox 4  1200

            Rotax 912 UL

---

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sun Mar 29, 2009 6:23 pm Post subject: Re: Near disaster

David has a very good point. You should get a low pressure gauge 

(10 psi max) and put it in line after the fuel pump and double check the fuel pressure on a tie down at full throttle. This is fairly easy to do and you don't need any special test gauge.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

darinh

Joined: 20 Apr 2006
Posts: 327
Location: Utah

Posted: Sun Mar 29, 2009 7:16 pm Post subject: Re: Near disaster

I agree with Deke...there is no need for filters before the header tank.  When I say I have 3 filters, I am including my finger strainers as one.  I have an Earl's filter before the pumps and a final filter forward of the firewall just before it goes into the pressure regulator.  Had my final filter not been there, all that disintegrated hose material would have ended up in my pressure regulator and carbs so it did serve a purpose.  After changing the hose, it is probably overkill to have the last filter but it is there.

_________________
Darin Hawkes
Series 7
914 Turbo
Kaysville, Utah

thesupe(at)hotmail.com
Guest

Posted: Mon Mar 30, 2009 5:02 am Post subject: Near disaster

After I had the problem with my plugged filter C I got rid of the filters that were before the header tank.  I then mounted another filter in parallel with the other one under the instrument panel.  I put in another valve that I could close off the second filter with.  I allways opened the valve for takeoff and would close it once I got above 500' or so.  My thinking was I then had a backup filter if the engine started to spit and miss from a plugged filter.  Jim Chuk  Avids C Kitfox 4  Mn

[quote] Subject: Kitfox-List: Re: Near disaster

 From: gerns25(at)netscape.net

 Date: Sun C 29 Mar 2009 20:16:53 -0700

 To: kitfox-list(at)matronics.com

 --> Kitfox-List message posted by: "darinh" <gerns25(at)netscape.net>

 I agree with Deke...there is no need for filters before the header tank. When I say I have 3 filters C I am including my finger strainers as one. I have an Earl's filter before the pumps and a final filter forward of the firewall just before it goes into the pressure regulator. Had my final filter not been there C all that disintegrated hose material would have ended up in my pressure regulator and carbs so it did serve a purpose. After changing the hose C it is probably overkill to have the last filter but it is there.

 --------

 Darin Hawkes

 Series 7 

 914 Turbo

 Kaysville C Utah

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=236799#236799

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